If your rear wiper doesn't move freely away from the glass when you pull it away from the vehicle, and pull back to the glass on it's own, then this is your problem.
I'm lucky enough to have 2 LR3s, so when one has a problem, it is easy to compare everything to the other that doesn't have any issue.
My wife's was having this issue with the rear wiper hanging, slowing, or stopping completely. When I checked the wiper, I found that her wiper arm would not pull out away from the glass at all, while mine moved freely on its pivot point and the spring would pull it right back against the glass as it should.
I sprayed the pivot point with WD40, and started pulling and pushing the arm away and toward the glass. I continued this until the arm was moving freely out, and the spring was pulling it right back to the glass. It took a lot more time of pulling in and out than I expected it to (maybe 40-50 times), but it eventually felt just like my good one. I went on and sprayed the pivot on mine just for preventative measure.
Her's is working like new now.